Titanium diboride articles and method for making same



United States Patent 3,215,545 TITANIUM DIBORIDE ARTICLES AND METHOD FORMAKING SAME Ronald W. Reid], Findlay, and Jurgen Hartwig, Fostoria,

Ohio, assignors to Union Carbide Corporation, a cor- 3,215,545 PatentedNov. 2, 1965 2 at about 10 tons per square inch and subsequentlysintered. Alternatievly, the mixture can be hot pressed.

In either method, the material is sintered at a temperature of fromabout 1800 C. to about 2150 C. A carbon tube furnace can be used in theheating step.

5 Porafion 9 York The resultin article has a density of about 90 percentN0 Drawmg' Flleil 1962 g? 247381 or more of the oretical andadditionally has substantially 7 Clalms' 106 improved strength over TiBwithout additive when proc- The present invention relates to highstrength, high essed i a i il manna; density titanium diboride articles-10 An advantage of the present invention is that relatively MoreParticularly, the Preseht invention relates to the low sinteringtemperatures, i.e. 1800 C. to 2150 C. use of niobium diboride andtungsten boride in the manucan b d to id a hi h density, high strength,fact ure of the aforesaid articles. ti le,

A continuing problem in the manufacture of titanium hi advantage iimportant Since i ll ildi articles y pressing and sintering is that ofable titanium diboride, without the addition of Nan, taihihg relativelyhigh density concurrently With high or W B requires sinteringtemperatures of about 2225 slrehgth- C. to provide high densitysintering, and at such tempera- With Presently known techniques,sihtel'ihg of titanium tures, excessive grain growth results in poorstrength in diboride provides articles af about 82-86 percent of h i d i1 theoretical density With good strehgth- Increasing the The ability touse relatively low sintering temperatures tefihg temperature Willimprove the density to some is also important when using carbon furnacessince the tent, however, excessive grain growth at higher p problem ofcarbon dissolution in the titanium diboride tures has the effect ofsubstantially reducing the strength i id d at h lower i t i temperaturesof the sint r d a s- With regard to the materials used in the presentinven- It is therefore an object of the present invention to h th tit idib id NbB d W B may be any provide a sintered titanium diboride articlehaving irncommercially il bl products,

PrWed density and high Strength The mixing of the materials ispreferably accomplished It is 8150 an Object of the Present invention toProvide by blending the mixture constituents during the ball millarelatively low tempertaure sintering process for produci ti g highdensity titanium diboride articles having high When using NbB as theadditive, a content of about Strength. 7.5 parts per hundred NbB in themixture is preferred.

other Objects Will be apparent from the following With W B as theadditive, a content of about 6 parts description and Claimsper hundredhas been found to provide highly satisfactory A titanium diboridearticle, in accordance with the l Present invention, is a Pressed andsintered miXhlTe of The following examples will further serve toillustrate titanium diboride with from about 3 to about 8 parts per hpresent invention hundred by weight of a material selected from thegroup EXAMPLE I consisting of NbB and W 3 The aforedescribed article ofthis invention is characterized by superior strength and Separatebatches of different proportions of commerdensity as compared to atitanium diboride article precially available titanium diboride andniobium diboride pared in the same manner without the use of theselected (98 percent Nb+B) were milled with /8" diameter stainmaterial.less steel balls for 48 hours. The resulting particles were In thepractice of the present invention, particles of provided with atemporary binder by applying 3 parts titanium diboride and between 3 and8 parts per per hundred epoxy resin in the form of an acetonesoluhundred of particles of the selected material, e.g., niobium tion.The resultant slurry was air dried to evolve acetone, diboride aremilled together in a ball mill to obtain a thus depositing resin on theTiB particles. Cylindrical good mixture of finely divided particles. Theparticle sizsamples 1" long x 1" in diameter were prepared from the ingin the mixture is not critical, however, the smaller various mixtures bycold pressing at 10 tons per in. the particle size, the higher will bethe density of the final The samples were subsequently sintered in anargon atarticle. An average particle size in the mixture of from 50mosphere in a carbon tube furnace by heating the furabout 1.5 to about3.0;. provides highly satisfactory renace at a rate of 400 C. per hourto a particular temperasults. ture between 1800 C. and 2150 C. and heldat this tem- After the foregoing treatment, the mixture is pressedperature for 3 hours. by conventional techniques to a suitable desiredsize and The resulting sintered articles were then subjected to shape.For example, the mixture can be cold pressed various measurements. Theresults are shown in Table I.

Table I Sintering Sintered Theoretical Percent of Mixture Tempera-Apparent Apparent Theoretical ture, 0. Density Density Apparent Density1,850 3.87 4. 52 85.7 TlBz 2, 000 3. s2 4. 52 84. 6 2, 3. as 4. 52 85. 51,850 3.87 4. 57 84. 6 TiBz-I-3D1Jh. NbBi 2,000 4.08 4. 57 89.4 2, 1304. 00 4. 57 87. 5 mt ta 2: i123 a; 1, 850 4. 00 4. 62 87.9 TlB2+6 pph.NbBz 2,000 4.25 4.02 92.1 2, 130 4. 27 4. e2 92. 5 m 53388 as 2122 as1,850 4. 00 4.68 85. 4 TlB2+10 pph. NbB2 2, 000 4. 03 4. 68 86.1 2, 1303.88 4. 68 82. 9

EXAMPLE 11 Mixtures prepared as in Example I were hot pressed at 2000p.s.i. in a 1" diameter cylindrical mold during heating in a carbon tubefurnace.

To hot press the mixtures, the furnace was first heated rapidly to 1000C. and then heated at 400 C. per hour to 1800 C. and held atthis'temperature for 1 hour. The hot pressed samples were then subjectedto various measurements. The results are shown in Table II.

EXAMPLE III Mixtures of titanium diboride and W B were prepared andsintered in the same manner as Example I.

The resulting sintered articles were subjected to various measurements,and the results are shown in Table III.

Table III Min. and Max. Percent Mixture of Theoretical Density for 5samples TiBz-j-fi pph. W2B 89. 6-93. 5

EXAMPLE IV Mixtures of titanium diboride and W 3 were prepared and hotpressed in the same manner as Example II.

The resulting articles were subjected to various measurements, and theresults are shown in Table IV.

Table IV Apparent Percent of Flexural Elastic Mixture DensityTheoretical Strength, Modulus Density p.s.i. X" p.s.i.

TIB2 4. 38 97 7, 500 65 TiBz-l-Ei pph. W2B 4. 43 96 44, 500 67 TiB +6pph. WzB5. 4. 55 97 34, 600 69 It is considered that the aforedescribedinvention repre sents a significant contribution to the art in providinga high density, high strength titanium diboride article which can beused eifectively in many applications such as for example, containersfor moltenaluminum and cathode lead in rods in aluminum production.

What is claimed is:

1. As an article of manufacture a pressed and sintered mixture oftitanium diboride and between 3 and 8 parts per hundred of a materialselected from the group consisting of NbB and W B said article beingcharacterized by high density and high strength.

2. As an article of manufacture a pressed and sintered mixture oftitanium diboride and about 7.5 parts per hundred NbB said article beingcharacterized by high density and high strength.

3. As an article of manufacture a pressed and sintered mixture oftitanium diboride and about 6 parts per hundred W B said article beingcharacterized by high density and high strength.

4. As an article of manufacture a pressed and sintered mixture oftitanium diboride and about 3 parts per hundred W B said article beingcharacterized by high density and high strength.

5. A process for producing high density, high strength titanium diboridearticles which comprises pressing and sintering a mixture consistingessentially of titanium diboride and between 3 and 8 parts per hundredof a material selected from the group consisting of NbB and W B themaximum sintering temperature being in the range of 1800 to 2150" C.

6. A process for producing high density, high strength titanium diboridearticles which comprises cold pressing and subsequently sintering amixture consisting essentially of titanium diboride and between 3 and 8parts per hundred of a material selected from the group consisting ofNbB and W B the maximum sintering temperature being in the range of 1800to 2150 C.

7. A process for producing high density, high strength titanium diboridearticles which comprises hot pressing a mixture consisting essentiallyof titanium diboride and between 3 and 8 parts per hundred of a materialselected from the group consisting of NbB and W B the maximum sinteringtemperature being in the range of 1800" to 2150" C.

References Cited by the Examiner UNITED STATES PATENTS 2,802,748 8/57Glaser 10655 TOBIAS E. LEVOW, Primary Examiner.

1. AS AN ARTICLE OF MANUFACTURE A PRESSED AND SINTERED MIXTURE OFTITANIUM DIBORIDE AND BETWEEN 3 AND 8 PARTS PER HUNDRED OF A MATERIALSELECTED FROM THE GROUP CONSISTING OF NBB2 AND W2B5, SAID ARTICLE BEINGCHARACTERIZED BY HIGH DENSITY AND HIGH STRENGTH.